---
title: Reference
sidebarTitle: Overview
---

These pages detail the core interfaces you will use when building with LangGraph. Each section covers a different part of the ecosystem.

## LangGraph

The core APIs for the LangGraph open source library.

:::python
- [Graphs](https://langchain-ai.github.io/langgraph/reference/graphs/): Main graph abstraction and usage.
- [Functional API](https://langchain-ai.github.io/langgraph/reference/func/): Functional programming interface for graphs.
- [Pregel](https://langchain-ai.github.io/langgraph/reference/pregel/): Pregel-inspired computation model.
- [Checkpointers](https://langchain-ai.github.io/langgraph/reference/checkpoints/): Saving and restoring graph state.
- [Storage](https://langchain-ai.github.io/langgraph/reference/store/): Storage backends and options.
- [Caching](https://langchain-ai.github.io/langgraph/reference/cache/): Caching mechanisms for performance.
- [Types](https://langchain-ai.github.io/langgraph/reference/types/): Type definitions for graph components.
- [Config](https://langchain-ai.github.io/langgraph/reference/config/): Configuration options.
- [Errors](https://langchain-ai.github.io/langgraph/reference/errors/): Error types and handling.
- [Constants](https://langchain-ai.github.io/langgraph/reference/constants/): Global constants.
- [Channels](https://langchain-ai.github.io/langgraph/reference/channels/): Message passing and channels.
:::

:::js
- [Graphs](https://langchain-ai.github.io/langgraphjs/reference/classes/langgraph.Graph.html): Main graph abstraction and usage.
- [Functional API](https://langchain-ai.github.io/langgraphjs/reference/modules/langgraph.html): Functional programming interface for graphs.
- [Pregel](https://langchain-ai.github.io/langgraphjs/reference/classes/langgraph.Pregel.html): Pregel-inspired computation model.
- [Checkpointers](https://langchain-ai.github.io/langgraphjs/reference/modules/checkpoint.html): Saving and restoring graph state.
- [MemorySaver](https://langchain-ai.github.io/langgraphjs/reference/classes/checkpoint.MemorySaver.html): Storage backends and options.
- [Errors](https://langchain-ai.github.io/langgraphjs/reference/variables/checkpoint.ERROR.html): Error types and handling.
- [Channels](https://langchain-ai.github.io/langgraphjs/reference/classes/langgraph_pregel.Channel.html): Message passing and channels.
:::

## Prebuilt components

Higher-level abstractions for common workflows, agents, and other patterns.

:::python
- [Agents](https://langchain-ai.github.io/langgraphjs/reference/functions/langgraph_prebuilt.createReactAgent.html): Built-in agent patterns.
- [Supervisor](https://langchain-ai.github.io/langgraphjs/reference/modules/langgraph_supervisor.html): Orchestration and delegation.
- [Swarm](https://langchain-ai.github.io/langgraphjs/reference/modules/langgraph_swarm.html): Multi-agent collaboration.
- [MCP adapters](https://langchain-ai.github.io/langgraph/reference/mcp/): Integrations with external systems.
:::

:::js
- [Agents](https://langchain-ai.github.io/langgraph/reference/agents/): Built-in agent patterns.
- [Supervisor](https://langchain-ai.github.io/langgraph/reference/supervisor/): Orchestration and delegation.
- [Swarm](https://langchain-ai.github.io/langgraph/reference/swarm/): Multi-agent collaboration.
:::
